In general mobile communication systems, a base station (BS) consists of a base transceiver station (BTS) that transmits and receives high-frequency wireless signals and a base station controller (BSC) that controls all operations of BS. For instance, BTS is a device composed of wireless transceivers, communicating with terminals through wireless links. BSC manages a plurality of BTSs; it is in charge of wireless channel setting, frequency hopping, handover, etc.
According to FIG. 1, mobile communication systems (2) are comprised of BSs (10) and antennas (20). BSs (10) are inclusive of BTSs and are controlled through BSCs. These mobile communication systems (2) test the signal transmitted/received by BTSs (10), identify the frequency characteristics, etc., of the transmitted/received high-frequency signals to determine whether the signals are normal, and take countermeasures when faults have occurred. During BTS (10) testing, however, signal distortions frequently occur in the transmitted/received high-frequency signals due to unnecessary signals, making the tests inaccurate because the signal distortion phenomenon occurs in certain frequency bands needed by BTS (10).